Mot-clé : Density

The land use and town planning are the tools we use to shape our living environments and their structure. Therefore, they determine in large part our communities’ energy consumption patterns and they have an impact on many factors of greenhouse gas emissions (GHG), in particular:

Building and maintaining facilities (type, size and choice of material);

Transporting people and goods;

Maintaining or losing natural spaces;

Heating and air-conditioning of buildings.

The land use of a community sets characteristics for at least one or two generations. Highways, museums and neighborhoods are built to last for several decades. Their location and choice of material, for example, may have impacts that lasts for their entire life cycle. In addition to reducing the energy costs of community facilities directly, urban development has an effect on the lifestyle and therefore helps reduce GHG emissions at source.

Climate change can be dealt with in many ways. Part of the solution lies in technical innovations and everyday actions. However, the best way to overcome together the barriers we cannot overcome individually is to bring about significant changes in the way we plan urban development, in order to align it with the challenges we now face. This conclusion is reached by many, both locally (Jean Charest - in French) and in the rest of the world (Carfree France – in French).

The arrival of the automobile disrupted the cities’ urban development. Dense cities, that were based on public transit and active transportation and where people had easy access to various services, proceeded to quickly spread out. The era of the tramway had already caused cities to expand beyond what nonmotorized travel modes previously allowed; but contrary to the car that would eventually replace it, the tramway helped establish relatively compact urban forms where active transportation kept its importance.

After the Second World War, with the car becoming popular, North America underwent a massive urbanization phase which happened to be based on what we now call sprawl, creating suburban areas located ever further from downtown. In this new context where density and accessibility were no longer priorities, zoning regulations were now oriented towards a strict separation of land uses in order to limit the inconveniences of certain activities. The urban structure changed and traveling distances increased. In the period between 1971 and 2006, where the population of the Quebec City census metropolitan area increased by 62%, the built area increased by 261% [2]. These planning choices ensured that the car became an essential part of most people’s transportation needs.

This now results in chronic road congestion problems which governments usually try to solve by increasing road capacity. Unfortunately, this solution is short-lived and has a negative impact on the urban structure. In fact, the new roads attract new residential or commercial developments and generate new trips that will take up 50 to 90% [3] of the additional road capacity. This phenomenon, which is known as induced traffic, is integral in reinforcing the vicious circle of automobile dependency where the new roads develop their own congestion problems which will temporarily be solved by the same short-term solution.

Public transport, GHG emissions and oil dependency

Over the last decades, the urban sprawl has increased travel distances and motorized travel, and has created a growing automobile dependency that caused a drastic increase of GHG emissions.

Proof of this is the increase of the car to population ratio. Between 2000 and 2009 in Quebec, the number of motor vehicles rose by 24% while population growth was only 6.1% [4]. The more vehicles on the road, the more total distance travelled increases. From 1990 to 2007, total distance travelled by motor vehicles in Quebec went from 50 to 71 billion kilometers [5].

During the same period between 1990 and 2007, while almost all of Quebec’s various industrial activities managed to reduce their GHG emissions, the road transportation industry increased them by 37% [6]. Today, the transportation industry is accountable for 43% of the total amount of GHG emissions in the province, of which close to 80% is caused by road transportation of people and goods. To reach the Kyoto protocol objectives (and Quebec’s of 20% below 1990 levels by 2020) is to imperatively act on this sector.

The improvements in the energy efficiency of vehicles appear insufficient to reverse the trend. Firstly because of the growing share of light trucks and other large vehicles in the car fleet [7], and secondly because the gains from better energy perfomance are offset by a faster increase in travelled distances.

A costly dependency

The car-based spatial organization of cities has various negative impacts, among which are:

The resulting impervious surfaces eliminate the natural processes of water retention and filtration.

Urban sprawl increases the costs of construction and maintenance of public networks and facilities, as well as energy consumption at the neighborhood level.

The highways and expressways block and restrict walking and biking trips, creating no man’s land where walking is, if not dangerous, at least unpractical and uncomfortable.

Increasing automobile traffic hinders social interaction and contributes to breaking up the social structure.

Reversing the trend: the logic of a compact city

When the urban structure adapts itself to the car, it becomes less and less compatible with other means of transportation that, in order to be efficient, need density.

The contribution of planning in improving the carbon footprint of our communities brings different benefits and takes into account the particular context of every living environment.

Since the 80s, the Smart Growth movement in North America has suggested a planning approach that focuses on the idea of a compact city. More recently, many cities provide planning examples that successfully implement the elements previously mentioned. This is the case, for example, for Stockholm in Sweden, and Portland in Oregon. There are also examples of model neighborhoods that are entirely built in accordance with the principles of the compact city. These ecodistricts, usually pilot studies that allow developers, builders and planners to develop skills and spread expertise, can lead to exemplary neighborhoods that become part of their city and offer an ideal living environment to their inhabitants. Well-known examples are the Vauban neighborhood, in Freiburg-im-Breisgau in Germany, and Hammarby, a neighborhood in Stockholm, Sweden.

There is no magic formula for the sustainable development of communities. It is fundamental that a large variety of elements and opinions be considered. That way, the various issues related to adequate land use planning can hopefully be dealt with appropriately.

If we choose to, public transit can be a major player in the fight against climate change. No matter what fuel it uses, public transport is able to replace a great number of automobile trips and reduce greenhouse gas (GHG) emissions. For example, a diesel bus needs only 7 passengers to emit less CO2 than the car trips it replaces, and the emissions related to hydroelectricity-powered mass transit networks are of course even much smaller. In any case, maximizing the impact of public transit on GHG reduction implies, first and foremost, that it is able to encourage more people to use it instead of their car.

During peak hours, a bus carries up to 65 passengers and a subway up to a 1000 – cars carry on average 1.2 person each.

Bus trips emit on average 7 times less GHGs per passenger for each kilometer travelled.

Tramways need on average 14 times less energy than a car in a typical urban environment to carry a passenger on one kilometer (and is generally powered by electricity) [1].

Benefits that go beyond GHGs reduction

Mass transit offers a multitude of environmental, social and economic benefits[2] and is, in many cases, significantly more efficient for the user. It thus makes personal as well as collective sense to implement and use them. In terms of social impacts, public transit is a more equitable mode of travel than the car and has positive impacts on the users’ health. In addition to being affordable to almost every citizen, it acts towards its users as a great incentive to be more active[3]:

In the United States, mass transit users walk on average 19 minutes per day, and approximately one third of them walk more than 30 minutes every day (the recommended daily physical activity duration);

Because of its impact on physical activity, use of public transit is associated with decreased rates of diabetes, stroke and cardiovascular accidents.

The economic benefits of public transit are often underestimated, even though it can act as a powerful lever for economic growth on national, regional and local levels.

In Quebec, investments in public transportation generate economic benefits three times higher than their equivalent in the automotive sector[4].

Public transit has positive impacts on the attractiveness and competitiveness of a region by inducing strong economic growth and a high quality of life.

Despite all these benefits however, less than 13% of Quebecers actually use public transit for their daily work commute. This is a situation that can be explained by many factors, not least among them being the way we plan and develop our communities.

Linking transport and planning

Because they heavily influence each other, land use planning and transport are inextricably linked. For example, sprawling and monofonctional urban forms foster automobile use, which needs highway infrastructure that in turn reinforces sprawl development and the separation of activities. But the same logic applies to mass transit the other way around: the presence of compact and mixed-use living environments increases the level of transit service and use that a community can sustain, while major transit routes induce compact real estate developments.

Tramway was part of the planning of the Vauban neighborhood from the beginning – Source: Vivre en Ville

Transit-oriented development (TOD) is a planning strategy founded on this principle and which aims to develop compact mixed-use communities with pedestrian-friendly urban design and higher densities around mass transit hubs[6]. TOD-based planning can be applied to new developments as well as being used as a tool for regeneration of existing neighborhoods. Residents of TOD neighborhoods are 5 times more likely to use public transit than their car-oriented neighborhood counterparts[7].

Improve service and boost ridership

For all the above reasons, promoting public transit in order to increase its modal share (the proportion of transit users to the overall commuters) is essential. It is also an objective the Quebec Government has given itself.

What are the main factors likely to make transit more attractive and help it compete with the car?

Quick and easy access to mass transit stops and stations;

Speed and frequency of service;

Capacity;

Service quality and comfort.

Longer operating hours, a bigger network and an increase in the number or routes generally leads to increased ridership. Estimates show that a 10% improvement of the service (by increasing the number of vehicle-km or vehicle-hours) generates a 6 to 10% increase in ridership. Better vehicles and more comfortable stops and stations do also contribute to ridership increases. Obviously, service improvements are dependent on funding! And finally, from another standpoint, the attractiveness of public transportation compared to that of the car may be increased through the adoption of more stringent standards and/or regulatory provisions, for example pertaining to parking or gas prices.

Intermodality: more flexible, more efficient

Intermodality is the only way by which public transit can offer its users the flexibility and efficiency it needs if it is to become a true alternative to the automobile. Intermodality means that on a single trip, a person could easily bike, ride the subway and finish his commute by a short walk to work. This flexibility strongly helps to foster a car-free accessibility to the city’s activities and services for its residents. A transportation system focusing on intermodality needs, obviously, intermodal hubs (places where at least two different transportation modes connect), but also real-time multimodal information and integrated transportation fares. Other measures can be implemented, such as bus-mounted bicycle racks or arrangements between transit and car-sharing companies.

Density, and notably residential density [1], is closely related to the issue of urban sprawl. Indeed, developing low-density neighborhoods implies to always set them a little farther on the outskirts, taking up large non-developed areas for a small number of residents.

Density and GHG emissions

The density of housing and activities has a significant impact on greenhouse gases emitted by a community, mainly because it determines the residents’ needs in motorized travel, especially by affecting the level of public transit services the community can sustain. Indeed, below a certain residential density, public transit becomes inefficient and very difficult to implement and/or pay for. Moreover, a dense environment encourages the use of active transportation[2]. The difference in density between two neighborhoods can generate an important difference in GHG emissions. For example, a community with a density of 43 housing units per hectare would emit 38% less GHG through its transportation-related activities alone than one with a 3.6 units/ha density, and 14% less than another with a 21 units/ha density![3]

Density, synonym of efficiency

Increasing residential density not only reduces GHG emissions but also lowers travel distances and energy consumption. But the benefits of a denser living environment go beyond the transportation issue, as it also lowers overall energy consumption. A single two-story house will experience 20% higher energy losses on average than a semi-detached, and 50% more than an apartment.

Moreover, density offers municipalities the opportunity to save money, since higher densities result in significant reductions in public expenditures[4], particularly for major infrastructures, roads, police and education services. In Toronto, studies[5] found that a more compact development of the region in the next 30 years would help lower the investments in buildings, transportation and public services (water and sewer pipes, etc.) by 10 to 16 billion dollars and the operating and maintenance costs by 2.1 to 4 billion dollars. Finally, compact living environments also increase businesses’ and local services’ viability and resilience.

Density, a misused concept. And yet…

Some people are reluctant to medium- to high-density environments for all kinds of reasons related to the quality of life which turn out to be unjustified most of the time. Residential density is far from being synonym for high-rise buildings! While ensuring a convenient density level, combining townhouses, duplex and triplex apartments can contribute to the making of pleasant, diversified and sustainable communities. In fact, when the concept of density is well implemented, it can be perfectly compatible with typical family needs like sufficient space, adequate privacy and green space. The quality and quantity of semi-private and public spaces make up for the sometimes smaller size of private spaces. In addition, such a lifestyle is also usually more economical for all.

Moreover, the benefits in terms of efficiency and profitability help dense environments offer residents a variety of services that are impossible to obtain in low-density environments. Parks, kindergartens, schools, businesses, public transit, leisure and cultural facilities… Compact communities make these services easily accessible and collectively affordable, for the benefit of all.

Solutions for our living environments

There are different mechanisms for action. Cities can do the following:

Make the redevelopment of wastelands a priority.

Make the zoning bylaw’s regulatory provisions on building height more flexible.

Impose a minimum density and authorize the densification of existing neighborhoods.

Restrict the urban boundary.

With a little creativity, there can be found many ways of increasing the density of existing neighborhoods without reducing the quality of life of current residents.

Garages transformed in housing units as part of the “laneway housing” program in Vancouver – Source: City of Vancouver

The EcoDensity project of the city of Vancouver is a good example of a practical application of these concepts. It encourages residents to build a second house in the backyard of their single family home by modifying their back-alley garage entrance. This initiative has also been called “Hidden Density”. Today, we can see a great variety of designs for these houses that are typically intended for aging parents or young adults.

Notes

[1] Residential density = number of housing units or inhabitants on a given area (hectare ou sq. km). ↩

[5] Christopher A. De Sousa, 2002. « Measuring the Public Costs and Benefits of Brownfield Versus Greenfield Development in the Greater Toronto Area », Environment and Planning B: Planning and Design, vol. 29. ↩

The development adopted by the communities since the 50s was based on using a lot of resources and land. Before the car and single-family detached home model, which lead to urban sprawl, cities were generally quite compact, with the ensuing benefits. But the possibility of traveling long distances quickly has changed the cities’ fabric. The agglomeration of Quebec City, which has seen its urban area grow by 248% between 1971 and 2001 while its population increased by only 42%, is a good example of such transformation [1]. Stretching the boundaries of urban development is often done at the expense of the environment and agriculture, an acute problem still today, as evidenced by the approval by the Commission de protection du territoire agricole to rezone, between 2001 and 2009, 7594 hectares of agricultural land [2] while thousands of hectares of non-agricultural land were available for urbanization.

Low-density residential neighborhood in the agglomeration of Quebec City – Source: APEL St-Charles

Apart from destroying these lands, the urban sprawl has a large number of negative consequences such as the following:

GHG emissions (due to automobile travel);

Impacts on the environment, air and water;

Health issues;

Iniquity in accessibility and bearing of negative impacts;

Maintenance costs of infrastructures.

Limit urbanization

Conversely, a more compact urban development provides many benefits if it is well planned. Establishing an urban perimeter that geographically limits development to a predetermined area is an effective way to counter sprawl and end an obsolete development model. Curbing the area available for urbanization needs careful planning and a balanced approach, particularly when the city faces the opposite trends of a growing population and a decreasing average household size, a common occurence in Quebec.

Development and land use planning

In Quebec, planning is the responsability of both the municipalities and the regional county municipalities (RCM). RCMs are responsible for the land-use and development plan that prescribes which areas of the land must be developed, and under which guidelines. Local municipalities, in accordance with these guidelines, must then adopt their own master plan, which that sets out their vision and defines specific land uses and density zones. At this stage, a municipality intent on efficiently curbing the sprawling urbanization trend it is experiencing can identify areas that must be strengthened in priority and demonstrate how it can be accomplished. There exists various misused and/or underused sectors or lots in every city that could benefit from urban renewal projects:

Municipalities can hugely benefit from being creative and proactive in their urban consolidation strategy and projects, and this creativity does not have to manifest itself only through the bylaws. Municipalities can for example implement programs of financial and/or fiscal incentives intended to redirect and better manage development in some parts of the city.

A PROJECT BY VIVRE EN VILLE

Vivre en Ville is an NGO dedicated to improving the quality of the natural and living environments in Quebec communities by promoting sustainable urban planning. Through research, demonstration projects and support programs, training tools and public events, Vivre en Ville stimulates innovation and participates in the development of sustainable communities, at the building, neighbourhood, city and metropolitan scales. You can support us by becoming a member.